1. Field of the Invention
This invention relates to a data recording/reproduction apparatus and a data recording/reproduction method for editing a plurality of data recorded on a recording medium adapted to non-linear data reproduction by defining a plurality of editing points.
2. Description of Related Background Art
In recent years, the number of channels available for transmitting information in the form of electric signals has been remarkably increased with the advent of CATV (cable television). As a result, there is a strong demand for apparatus adapted to simultaneously record a number of different sets of audio/video data and/or reproduce such data from a single audio/video data recording/reproduction apparatus. To meet this demand, apparatus called video servers and adapted to record and reproduce audio/video data have been developed and widely marketed.
A video server is typically connected to a number of large capacity hard disc drives adapted to non-linear data reproduction to make the total recording capacity amount to tens to hundreds of several gigabytes. Such a video server is suited to record a huge volume of data including audio data and video data. Particularly, with a video server, any selected audio data or video data can be accessed in a very short period of time so that it can advantageously be used as recording/reproduction apparatus applied to editing data.
The video server maintains information for managing the locations where the files store in each hard disc are actually found and the information is used to manage the audio/video data recorded on the hard disc. Additionally, when the video server is used to edit audio/video data, it prepares file editing information that is referred to as VFL (virtual file list) and include continuous data length information. Thus, an editing operation proceeds as a VFL is prepared by means of the video server by specifying and retrieving file name information and continuous data length information. The video server simply reproduces the VFL without re-recoding the retrieved audio/video data on a hard disc during the editing operation and then reads the edited audio/video data from the related hard disc by referring to the VFL during the subsequent replay operation.
Japanese Patent Application No. 7-320185 (Japanese Patent Application Laid-Open Publication No. 9-163310) and U.S. Pat. No. 5,841,740 disclose a technology on the VFL invented by the applicant of the present patent application.
Now, the technology disclosed in the above patent documents will be described below.
Assume that file A and file B, both containing audio and/or video data, are stored on a hard disc in a video server as shown in FIG. 1A. FIG. 1A is a schematic illustration of the address space on a hard disc. The file A is recorded continuously at addresses 170 through 230 on the hard disc, using a total of sixty addresses. On the other hand, the file B is recorded at addresses 80 through 130 and 230 through 330. In other words, the file B is recorded discontinuously on the hard disc.
In the video server, the information showing the location of each of the files recorded on the corresponding hard disc of the video server is stored in a predetermined memory. FIGS. 1B and 1C illustrate the file system information of the file A and that of the file B. The file system information of the video server includes file entries and record entries. Each file entry contains the file name and the pointer information for pointing the corresponding record entry. Each record entry contains the address of the head of each continuous recording area and the length of the continuous recording area from the head.
As shown in FIG. 1A and described above, the file A is recorded continuously at addresses 170 through 230 on the hard disc, using a total of sixty addresses. Since the file A is not recorded in any other area, the file system information of the file A includes a file entry containing the fine name “A” and the pointer information for pointing the corresponding record entry and a record entry containing the location of the head, or address “170”, the continuous recording area for “60” addresses starting from there and “END” indicating that the file A is not stored in any other area.
Also as shown in FIG. 1A and described above, the file system information of the file B that is stored discontinuously on the hard disc includes a file entry containing the file name “B” and the pointer information for pointing the corresponding record entry and a record entry containing the location of the head, or address “80”, the continuous recording area for “50” addresses starting from there, the location of the next head, or address “230”, the continuous recording area for “100” addresses starting from there and “END” indicating that the file B is not stored any other area.
The files recorded in the video server are then managed by means of the file system information and, for instance, a replay instruction specifying a file is input from the host, the video server confirms the address value to be accessed by using the file system information so that it can actually access the file stored on a specific hard disc and reproduce the data of the file.
Now, an operation of editing some of the files stored in the video server by using an editing machine connected to the video server on the basis of the file system will be discussed below. Assume that the editing operation consists in connecting part of the file A and part of the file B to produce a new file.
Firstly, both the file A and the file B are reproduced from the video server and sent to the editing machine. Assume here that the position at the 10-th address as counted from the head of the file A is the replay starting point (IN point) and the position at the 50-th address as counted form the head of the file A is the replay ending point (OUT point) of the file A, whereas the position at the 20-th address as counted from the head of the file B is the replay starting point (IN-point) and the position at the 60-th address as counted from the head of the file B is the replay ending point (OUT-point) of the file B. Then, the editing machine edits the files A and B by following a predetermined editing sequence.
When the editing machine completes the operation of editing the two files, it sends the file of audio and/or video data produced as a result of the editing operation back to the video server. A VFL shows the data indicating the outcome of the editing operation.
A VFL will be described by referring to FIGS. 2A and 2B.
As shown in FIGS. 2A and 2B, the VFL shows the file names and the replay starting position and the replay ending position of each of the files. The replay stating position and the replay ending position are indicates by the respective address values obtained by defining the address of the head of the file as address 0. It will be seen that FIGS. 2A and 2B show the VFL for the file A and the file B.
Upon receiving the VFL as input, the video server prepares file system information (on file name “X”) independently from the above described file system information.
More specifically, since the head position of the file A is known to be as “170” from the file system information on the file A as shown in FIG. 1B, the actual IN-point on the hard disc is 170+10, or “180”. As data are recorded continuously for an area corresponding to 40 addresses (=50−10), the continuous recording area is “40”. On the other hand, the head position of the file B is known to be as “100” from the file system information on the file B and data are recorded for an area corresponding to 40 addresses from the VFL. However, the data are recorded only continuously down to address “130” so that the data corresponding to 10 addresses are not found there because the head position is “100”. Then, the next continuous area starts from “230” and therefore all the data from the IN-point to the OUT-point can be reproduced by adding the data for “10” addresses starting from address “230”. Thus, the file system information on the file “X” obtained by the editing operation will be like the one shown in FIG. 2B.
Note that “ON” or “OFF” may be shown in the bottom row of each file entry to represents an erasable flag. However, since the files have to be erased after the editing operation, “OFF” is actually shown at the bottom of each file entry.
With the above arrangement, when reproducing the file obtained by the editing operation from the video server, it is now possible to reproduce the file on the basis of the file system information on the file “X”.
Now, when editing files by means of the video server, it is possible to use a technique of special effects to the video data (to be referred to as video effects) near the IN-point from which a file is selected and the OUT-point at which the selection of the file ends according to the intension of the editor.
However, when realizing such video effects, conventionally, it is necessary to read the two files, if two files are involved, from the hard disc by way of different respective ports, processing the files for the video effects and then recording them on the hard disc or some other hard disc before they are reproduced. Therefore, with the conventional editing technique involving the video effects, the files subjected to the operation of processing them for the video effects need to be recorded repeatedly on the hard discs to consume the limited resource of hard discs.